README.md

MapReduce

The aim of this project is to implement a distributed, fault-tolerant MapReduce framework using elixir language.

Installation

This project is available in Hex, and can be installed by adding map_reduce to your list of dependencies in mix.exs:

def deps do
  [
    {:map_reduce, "~> 0.2.0"}
  ]
end

Usage Guide

You have to define two functions, map and reduce, depending on the problem you want to solve. Let's say we want to solve the famous word count problem. Here's how you can define your map & reduce functions:

mapper = fn {_document, words} -> Enum.map(words, fn word -> {word, 1} end) end
reducer = fn {word, values} -> {word, Enum.reduce(values, 0, fn x, acc -> x + acc end)} end

Then you can use the MapReduce module to calculate the answer for your desired list:

list = [{"document_name", ["a", "b", "a", "aa", "a"]}]
MapReduce.solve(list, mapper, reducer) # you should get %{"a" => 3, "aa" => 1, "b" => 1} 

Note that here we used anonymous functions, you can use normal functions but you have to use the syntax MapReduce.solve(list, &mapper, &reducer) in that case

License

The source code is released under MIT License.

Check LICENSE for more information.